/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.response;

import org.apache.solr.request.SolrQueryRequest;
import org.apache.velocity.runtime.resource.loader.ResourceLoader;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.commons.collections.ExtendedProperties;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class SolrParamResourceLoader extends ResourceLoader {
	private Map<String, String> templates = new HashMap<String, String>();

	public SolrParamResourceLoader(SolrQueryRequest request) {
		super();

		// TODO: Consider using content streams, but need a template name
		// associated with each stream
		// for now, a custom param convention of template.<name>=<template body>
		// is a nice example
		// of per-request overrides of templates

		org.apache.solr.common.params.SolrParams params = request.getParams();
		Iterator<String> names = params.getParameterNamesIterator();
		while (names.hasNext()) {
			String name = names.next();

			if (name.startsWith("v.template.")) {
				templates.put(name.substring(11) + ".vm", params.get(name));
			}
		}
	}

	@Override
	public void init(ExtendedProperties extendedProperties) {
	}

	@Override
	public InputStream getResourceStream(String s)
			throws ResourceNotFoundException {
		String template = templates.get(s);
		try {
			return template == null ? null : new ByteArrayInputStream(
					template.getBytes("UTF-8"));
		} catch (UnsupportedEncodingException e) {
			throw new RuntimeException(e); // may not happen
		}
	}

	@Override
	public boolean isSourceModified(Resource resource) {
		return false;
	}

	@Override
	public long getLastModified(Resource resource) {
		return 0;
	}
}
